Implantable electric stimulation system and methods of making and using

ABSTRACT

A lead assembly includes a lead with a distal end and a proximal end. The lead includes a plurality of electrodes disposed at the distal end and a plurality of terminals disposed at the proximal end. The lead also defines at least one central lumen and a plurality of outer lumens. The central and outer lumens extend from the proximal end to the distal end such that the plurality of outer lumens extend laterally from the at least one central lumen. The lead further includes a plurality of conductive wires. Each conductive wire couples at least one of the plurality of electrodes electrically to at least one of the plurality of terminals. At least two conductive wires are disposed in each of the plurality of outer lumens.

TECHNICAL FIELD

The present invention is directed to the area of implantable electricalstimulation systems and methods of making and using the systems. Thepresent invention is also directed to implantable electrical stimulationsystems that include a lead utilizing strategies to increase the numberof electrodes preferably without a corresponding increase in the lateralcircumference of the lead, as well as methods of making and using theleads and electrical stimulation systems.

BACKGROUND

Implantable electrical stimulation systems have proven therapeutic in avariety of diseases and disorders. For example, spinal cord stimulationsystems have been used as a therapeutic modality for the treatment ofchronic pain syndromes. Deep brain stimulation has also been useful fortreating refractory chronic pain syndromes and has been applied to treatmovement disorders and epilepsy. Peripheral nerve stimulation has beenused to treat chronic pain syndrome and incontinence, with a number ofother applications under investigation. Functional electricalstimulation systems have been applied to restore some functionality toparalyzed extremities in spinal cord injury patients. Moreover,electrical stimulation systems can be implanted subcutaneously tostimulate subcutaneous tissue including subcutaneous nerves such as theoccipital nerve.

Stimulators have been developed to provide therapy for a variety oftreatments. A stimulator can include a control module (with a pulsegenerator), one or more leads, and an array of stimulator electrodes oneach lead. The stimulator electrodes are in contact with or near thenerves, muscles, or other tissue to be stimulated. The pulse generatorin the control module generates electrical pulses that are delivered bythe electrodes to body tissue.

BRIEF SUMMARY

In one embodiment, a lead assembly includes a lead with a distal end anda proximal end. The lead includes a plurality of electrodes disposed atthe distal end and a plurality of terminals disposed at the proximalend. The lead also defines at least one central lumen and a plurality ofouter lumens. The central and outer lumens extend from the proximal endto the distal end such that the plurality of outer lumens extendlaterally from the at least one central lumen. The lead further includesa plurality of conductive wires. Each conductive wire couples at leastone of the plurality of electrodes electrically to at least one of theplurality of terminals. At least two conductive wires are disposed ineach of the plurality of outer lumens.

In another embodiment, an electrical stimulating system includes a lead,a control module, and a connector. The lead includes a plurality ofelectrodes disposed at the distal end and a plurality of terminalsdisposed at the proximal end. The lead also defines at least one centrallumen and a plurality of outer lumens. The central and outer lumensextend from the proximal end to the distal end such that the pluralityof outer lumens extend laterally from the at least one central lumen.The lead further includes a plurality of conductive wires. Eachconductive wire couples at least one of the plurality of electrodeselectrically to at least one of the plurality of terminals. At least twoconductive wires are disposed in each of the plurality of outer lumens.The control module is configured and arranged to electrically couple tothe lead. The control module includes a housing and an electronicsubassembly disposed in the housing. The connector is configured andarranged for receiving the lead. The connector includes a connectorhousing and a plurality of connector contacts disposed in the connectorhousing. The connector housing defines at least one port for receivingthe proximal end of the lead. The connector contacts are configured andarranged to couple to at least one terminal disposed at the proximal endof the lead.

In yet another embodiment, a method for making a lead includes placing asubstantially tubular-shaped lead body, with a proximal end and a distalend, into a mold with mold cavities between spaced-apart cylindricalpockets. The lead body includes a plurality of conductive wires in eachof a plurality of outer lumens. The outer lumens extend out of both theproximal end and the distal end of the lead body. A plurality ofterminals are disposed over the portion of the outer lumens extendingout of the proximal end of the lead body so that the each terminalaligns with a different cylindrical pocket. Each terminal iselectrically coupled to a different conductive wire. A plurality ofelectrodes are disposed over the portion of the outer lumens extendingout of the distal end of the lead body so that the each electrode alignswith a different cylindrical pocket. Each electrode is electricallycoupling to a different conductive wire. Resin is injected into the moldcavities between the spaced-apart cylindrical pockets.

BRIEF DESCRIPTION OF THE DRAWINGS

Non-limiting and non-exhaustive embodiments of the present invention aredescribed with reference to the following drawings. In the drawings,like reference numerals refer to like parts throughout the variousfigures unless otherwise specified.

For a better understanding of the present invention, reference will bemade to the following Detailed Description, which is to be read inassociation with the accompanying drawings, wherein:

FIG. 1 is a schematic view of one embodiment of an electricalstimulation system, according to the invention;

FIG. 2A is a schematic view of one embodiment of a proximal portion of alead and a control module of an electrical stimulation system, accordingto the invention;

FIG. 2B is a schematic view of one embodiment of a proximal portion of alead and a lead extension of an electrical stimulation system, accordingto the invention;

FIG. 3 is a schematic view of another embodiment of a proximal portionof a lead and a lead splitter of an electrical stimulation system,according to the invention;

FIG. 4 is a schematic side view of a portion of a distal end of acurrently-known lead of an electrical stimulation system, according tothe invention;

FIG. 5 is a schematic side view of another embodiment of a portion of adistal end of a lead of an electrical stimulation system, according tothe invention;

FIG. 6 is a schematic transverse cross-sectional view of one embodimentof the lead shown in FIG. 4, according to the invention;

FIG. 7A is a schematic transverse cross-sectional view of one embodimentof the lead shown in FIG. 5, according to the invention;

FIG. 7B is a schematic transverse cross-sectional view of a secondembodiment of the lead shown in FIG. 5, according to the invention;

FIG. 7C is a schematic transverse cross-sectional view of a thirdembodiment of the lead shown in FIG. 5, according to the invention;

FIG. 7D is a schematic transverse cross-sectional view of a fourthembodiment of the lead shown in FIG. 5, according to the invention;

FIG. 8 is a schematic transverse cross-sectional view of one embodimentof a lead with a conductive wire disposed in each outer lumen of thelead shown in FIG. 4, according to the invention;

FIG. 9A is a schematic transverse cross-sectional view of one embodimentof a lead with a conductive wire disposed in each outer lumen of thelead shown in FIG. 5, according to the invention;

FIG. 9B is a schematic transverse cross-sectional view of one embodimentof a lead with multiple conductive wires disposed in each outer lumen ofthe lead shown in FIG. 5, according to the invention;

FIG. 9C is a schematic transverse cross-sectional view of a secondembodiment of a lead with multiple conductive wires disposed in eachouter lumen of the lead shown in FIG. 5, according to the invention;

FIG. 9D is a schematic transverse cross-sectional view of a thirdembodiment of a lead with multiple conductive wires disposed in eachouter lumen of the lead shown in FIG. 5, according to the invention;

FIG. 10A is a schematic side view of one embodiment of a portion of aproximal end of a lead of an electrical stimulation system, according tothe invention;

FIG. 10B is a schematic side view of one embodiment of a portion of anend plug configured and arranged for disposal in a proximal end of alead of an electrical stimulation system, according to the invention;

FIG. 10C is a schematic side view of one embodiment of an end plugdisposed in a proximal end of a lead of an electrical stimulationsystem, according to the invention;

FIG. 10D is a schematic transverse cross-sectional view of oneembodiment of a rod disposed in a central lumen of the proximal end ofthe lead shown in FIG. 11C, according to the invention;

FIG. 11A is a schematic side view of one embodiment of a portion of aproximal end of a lead with oversized terminals and an oversized end capand without spacers inserted between adjacent terminals and between themost proximal terminal and the end cap, according to the invention;

FIG. 11B is a schematic side view of one embodiment of the portion ofthe proximal end of the lead shown in FIG. 11A with resin injectedbetween adjacent terminals and between the most proximal terminal andthe end cap, according to the invention;

FIG. 11C is a schematic side view of one embodiment of the portion ofthe proximal end of the lead shown in FIG. 11B after the terminals andthe end cap have been ground, according to the invention; and

FIG. 12 is a schematic overview of one embodiment of components of astimulation system, including an electronic subassembly disposed withina control module, according to the invention.

DETAILED DESCRIPTION

The present invention is directed to the area of implantable electricalstimulation systems and methods of making and using the systems. Thepresent invention is also directed to implantable electrical stimulationsystems that include a lead with an increased number of electrodeswithout a corresponding increase in the lateral circumference of thelead, as well as methods of making and using the leads and electricalstimulation systems.

Suitable implantable electrical stimulation systems include, but are notlimited to, an electrode lead (“lead”) with one or more electrodesdisposed on a distal end of the lead and one or more terminals disposedon one or more proximal ends of the lead. Leads include, for example,percutaneous leads, paddle leads, and cuff leads. Examples of electricalstimulation systems with leads are found in, for example, U.S. Pat. Nos.6,181,969; 6,516,227; 6,609,029; 6,609,032; and 6,741,892; and U.S.patent application Ser. Nos. 10/353,101, 10/503,281, 11/238,240;11/319,291; 11/327,880; 11/375,638; 11/393,991; and 11/396,309, all ofwhich are incorporated by reference.

FIG. 1 illustrates schematically one embodiment of an electricalstimulation system 100. The electrical stimulation system 100 includes acontrol module (e.g., a stimulator or pulse generator) 102 and at leastone percutaneous lead (“lead”) 106 that includes an array of electrodes134 at a distal end. The control module 102 typically includes anelectronic subassembly 110 and an optional power source 120 disposed ina sealed housing 114. The control module 102 typically includes aconnector 144 (see also FIG. 2A, and 222 and 250 of FIG. 2B) into whichthe proximal end of the one or more leads 106 can be plugged to make anelectrical connection via connector contacts on the control module 102and terminals (e.g., 210 in FIG. 2A and 236 of FIG. 2B) on each of theone or more leads 106. It will be understood that the electricalstimulation system can include more, fewer, or different components andcan have a variety of different configurations including thoseconfigurations disclosed in the electrical stimulation system referencescited herein. A lead may be isodiametric along the length of the lead.In addition, one or more lead extensions 212 (see FIG. 2B) can bedisposed between the one or more leads 106 and the control module 102 toextend the distance between the one or more leads 106 and the controlmodule 102 of the embodiment shown in FIG. 1.

The electrical stimulation system or components of the electricalstimulation system, including one or more of the leads 106 and thecontrol module 102, are typically implanted into the body of a patient.The electrical stimulation system can be used for a variety ofapplications including, but not limited to, brain stimulation, neuralstimulation, spinal cord stimulation, muscle stimulation, and the like.

The electrodes 134 can be formed using any conductive, biocompatiblematerial. Examples of suitable materials include metals, alloys,conductive polymers, conductive carbon, and the like, as well ascombinations thereof. The number of electrodes 134 in the array ofelectrodes 134 may vary. For example, there can be two, four, six,eight, ten, twelve, fourteen, sixteen, or more electrodes 134. As willbe recognized, other numbers of electrodes 134 may also be used.

The electrodes of the one or more leads 106 are typically disposed in,or separated by, a non-conductive, biocompatible material including, forexample, silicone, polyurethane, polyetheretherketone (“PEEK”), epoxy,and the like or combinations thereof. The one or more leads 106 may beformed in the desired shape by any process including, for example,molding (including injection molding), casting, and the like. Electrodesand connecting wires can be disposed onto or within a paddle body eitherprior to or subsequent to a molding or casting process. Thenon-conductive material typically extends from the distal end of thelead to the proximal end of each of the one or more leads 106.

Terminals (e.g., 210 in FIG. 2A and 236 of FIG. 2B) are typicallydisposed at the proximal end of the one or more leads 106 for connectionto corresponding connector contacts (e.g., 214 in FIG. 2A and 240 ofFIG. 2B) in connectors (e.g., 144 in FIGS. 1-2A and 222 and 250 of FIG.2B) disposed on, for example, the control module 102 (or to otherdevices, such as connector contacts on a lead extension, an operatingroom cable, or an adaptor). Conductive wires (not shown) extend from theterminals (e.g., 210 in FIG. 2A and 236 of FIG. 2B) to the electrodes134. Typically, one or more electrodes 134 are electrically coupled to aterminal (e.g., 210 in FIG. 2A and 236 of FIG. 2B). In some embodiments,each terminal (e.g., 210 in FIG. 2A and 236 of FIG. 2B) is onlyconnected to one electrode 134. The conductive wires may be embedded inthe non-conductive material of the lead or can be disposed in one ormore lumens (not shown) extending along the lead. In some embodiments,there is an individual lumen for each conductive wire. In otherembodiments, two or more conductive wires may extend through a lumen.There may also be one or more lumens (not shown) that open at, or near,the proximal end of the lead, for example, for inserting a stylet rod tofacilitate placement of the lead within a body of a patient.Additionally, there may also be one or more lumens (not shown) that openat, or near, the distal end of the lead, for example, for infusion ofdrugs or medication into the site of implantation of the paddle body104. In at least one embodiment, the one or more lumens may be flushedcontinually, or on a regular basis, with saline, epidural fluid, or thelike. In at least some embodiments, the one or more lumens can bepermanently or removably sealable at the distal end.

In at least some embodiments, leads are coupled with connectors disposedas part of a control module. In at least some embodiments, leads arecoupled with connectors disposed on lead extensions. In otherembodiments, leads are coupled with connectors disposed on otherdevices, such as an operating room cable or an adaptor. In at least someembodiments, fastening assemblies can be used to secure a coupling of alead with a connector. In FIG. 2A, the connector 144 is shown disposedon the control module 102. The connector 144 includes a connectorhousing 202. The connector housing 202 defines at least one port 204into which a proximal end 206 of a lead 208 with terminals 210 can beinserted, as shown by directional arrow 212. The connector housing 202also includes a plurality of connector contacts 214 for each port 204.When the lead 208 is inserted into the port 204, the connector contacts214 can be aligned with the terminals 210 on the lead 208 toelectrically couple the control module 102 to the electrodes (134 ofFIG. 1) disposed at a distal end of the lead 208. Examples of connectorsin control modules are found in, for example, U.S. Pat. No. 7,244,150and U.S. patent application Ser. No. 11/532,844, which are incorporatedby reference.

In FIG. 2B, a connector 222 is disposed on a lead extension 224. Theconnector 222 is shown disposed at a distal end 226 of the leadextension 224. The connector 222 includes a connector housing 228. Theconnector housing 228 defines at least one port 230 into which aproximal end 232 of a lead 234 with terminals 236 can be inserted, asshown by directional arrow 238. The connector housing 228 also includesa plurality of connector contacts 240. When the lead 234 is insertedinto the port 230, the connector contacts 240 disposed in the connectorhousing 228 can be aligned with the terminals 236 on the lead 234 toelectrically couple the lead extension 224 to the electrodes (134 ofFIG. 1) disposed at a distal end (not shown) of the lead 234.

In at least some embodiments, the proximal end of a lead extension issimilarly configured and arranged to a proximal end of a lead. The leadextension 224 may include a plurality of conductive wires (not shown)that electrically couple the connector contacts 240 to a proximal end248 of the lead extension 224 that is opposite to the distal end 226. Inat least some embodiments, the conductive wires disposed in the leadextension 224 can be electrically coupled to a plurality of terminals(not shown) disposed on the proximal end 248 of the lead extension 224.In at least some embodiments, the proximal end 248 of the lead extension224 is configured and arranged for insertion into a connector disposedin another lead extension. In other embodiments, the proximal end 248 ofthe lead extension 224 is configured and arranged for insertion into aconnector disposed in a control module. For example, in FIG. 2B theproximal end 248 of the lead extension 224 is inserted into a connector250 disposed in a control module 252. Note that, when a lead includestwo or more proximal ends, each proximal end can be inserted into one ofa plurality of ports defined in a connector, with each port including aplurality of connector contacts.

Sometimes a patient may be experiencing pain that extends to an areagreater in length than the length of an array of electrodes (e.g., 134of FIG. 1) disposed on the distal end of a particular lead. For example,a patient may experience pain in an area spanning multiple vertebralbodies. One way to increase stimulation coverage is to provide a leadwith a greater length and either increase the amount of space betweenadjacent electrodes, or increase the size of one or more of theelectrodes. However, when the amount of space between adjacentelectrodes is increased or the size of one or more of the electrodes inincreased, linear electrode density may decrease to a sub-therapeuticlevel.

Another way to increase stimulation coverage is to provide a lead with agreater length and increase the number of electrodes on the lead. A leadwith additional electrodes may include additional conductive wires. Whenan increased number of conductive wires are utilized, existing controlmodules may not be compatible with the lead. One option is to redesign acontrol module to accommodate the additional electrodes. A redesignedcontrol module may include a larger-sized connector, as well as acorresponding increase in the size or complexity of associatedelectronics. A larger-sized connector and additional electronicsdisposed in a control module may increase the size of the control moduleand accordingly make the control module difficult to manufacture or lessconvenient to implant in a patient. Additionally, an increased number ofconductive wires extending the length of a lead can increase the lateralcircumference of a lead, which may decrease the maneuverability orimplantability of the lead and also potentially reducing the number ofpotential implantation locations.

In at least some embodiments, more stimulation coverage can be providedwithout increasing the size or the complexity of a corresponding controlmodule. In at least some embodiments, a proximal end of a lead with anincreased number of conductive wires is inserted into a connectordisposed on a lead splitter with multiple proximal tails. Each proximaltail is configured and arranged to electrically couple electrodesdisposed on the lead to at least one connector contact disposed in aconnector disposed on a control module. Thus, in at least someembodiments, each proximal tail of the lead splitter can plug into aseparate connector on the control module.

FIG. 3 is a schematic view of another embodiment of a proximal end of alead 302 configured and arranged for insertion into a lead splitter 304that is electrically coupled to a control module 306. The lead splitter304 includes a connector 308 and proximal tails 310 and 312. Theconnector 308 defines a port 314 that includes a plurality of conductorcontacts 316 disposed in the port 314. The lead 302 includes a pluralityof terminals 318 on a proximal end 320 that are configured and arrangedfor insertion into the port 314 for electrically coupling with theplurality of conductor contacts 316. The proximal tails 310 and 312 eachinclude a distal end 322 and a proximal end 324. Each of the distal ends322 is coupled to at least one of the plurality of conductor contacts316. Each of the proximal ends 324 is configured and arranged to coupleto other connectors, such as the connector 326 disposed in the controlmodule 306, via conductive wires (not shown). For example, conductivewires disposed in the proximal tail 310 extend the longitudinal lengthof the proximal tail 310 and electrically couple one or more of theplurality of connector contacts 316 to the connector contacts 328disposed in the connector 326.

In at least some embodiments, approximately half of the connectorcontacts 316 electrically couple with conductive wires extending thelongitudinal length of the proximal tail 310 and half of the connectorcontacts 316 electrically couple with conductive wires extending thelongitudinal length of the proximal tail 312. In one embodiment, thelead 302 includes sixteen terminals 318 corresponding with sixteenelectrodes (not shown). The connector 308 includes sixteen conductorcontacts 316 configured and arranged to electrically couple with thesixteen terminals 318 of the lead 302. Eight conductive wires aredisposed in the proximal tail 310 and electrically couple with eight ofthe sixteen conductor contacts 316, while eight other conductive wiresare disposed in the proximal tail 312 and electrically couple with theremaining eight of the sixteen conductor contacts 316.

The number of proximal tails 310 and 312 disposed on the lead splitter304 may vary. For example, there can be two, four, six, eight, ten,twelve, fourteen, sixteen, or more proximal tails 310 and 312. As willbe recognized, other numbers of proximal tails 310 and 312 may also beused. Accordingly, in some embodiments, each proximal tail 310 and 312electrically couples a portion of the connector contacts 316 to two ormore control modules. Thus, two or more control modules may be used toprovide electric signals to a plurality of electrodes disposed on thelead 302.

In FIG. 3 and in subsequent figures, eight electrodes are used as anexample of the number of electrodes disposed on a distal end of a lead.Thus, sixteen electrodes are used as an example of a doubling of thenumber of electrodes disposed on a distal end of a lead. Additionally,sixteen terminals, sixteen connector contacts, and sixteen conductivewires are used as examples of a one-to-one relationship between thenumber of electrodes and the number of corresponding terminals,connector contacts, and conductive wires disposed on leads andcorresponding connectors when the number of electrodes disposed on alead is doubled. The numbers eight and sixteen and the one-to-onerelationship are used merely for the purposes of illustration. Othernumbers of electrodes may be disposed on a lead and other non-one-to-onerelationships may likewise be used in at least some embodiments. Forexample, in alternate embodiments, a lead may have eight electrodes thatelectrically couple with four terminals. The six terminals may, in turn,electrically couple with eight connector contacts.

In at least some embodiments, the number of electrodes disposed on alead can be increased up to a factor of two from a conventional numberof electrodes without increasing the lateral circumference of the lead.Thus, in at least some embodiments, additional electrodes can be addedto conventional leads, while still allowing the leads with additionalelectrodes to be compatible with conventional control modules. FIG. 4 isa schematic side view of one embodiment of a portion of a distal end ofan exemplary conventional lead 402. The exemplary conventional lead 402includes a plurality of electrodes 404, such as electrode 406, disposedon a distal end 408 of the exemplary conventional lead 402. Additionalfeatures of the exemplary conventional lead 402 are described below,with respect to FIGS. 6 and 8, for comparison with at least seineembodiments.

FIG. 5 is a schematic side view of one embodiment of a portion of adistal end of a lead 502 with a lateral circumference that is equal tothe lateral circumference of the exemplary conventional lead 402, butthat includes twice the number of electrodes from the lead 402. The lead502 includes a plurality of electrodes 504, such as electrode 506,disposed on a distal end 508 of the lead 502. The plurality ofelectrodes 504 is greater than the plurality of electrodes 404 in FIG. 4without a corresponding increase in the lateral circumference of thelead 502. In a preferred embodiment, the number of electrodes disposedon the lead 502 is twice the number of electrodes disposed on the lead402. For example, in FIG. 4, eight electrodes are shown on the lead 402,while in FIG. 5 sixteen electrodes are shown on the lead 502. In oneembodiment, the leads 402 and 502 are each isodiametric and have alateral diameter of 0.053 inches (0.135 cm).

Conductive wires may be used to electrically couple electrodes on adistal end of a lead to terminals on a proximal end of a lead. Asdiscussed above, with reference to FIG. 1, conductive wires may beembedded in the non-conductive material of the lead or can be disposedin one or more lumens extending along the lead. In some embodiments,each individual conductive wire is disposed in an individual lumen. FIG.6 is a schematic transverse cross-sectional view of the distal end ofthe exemplary conventional lead 402 shown in FIG. 4. In FIG. 6, the lead402 includes a center lumen 602 and a plurality of outer lumens 604-611.Each outer lumen 604-611 is configured and arranged for an individualconductive wire to extend along the length of each individual outerlumen 604-611. In FIG. 6, eight circular-shaped outer lumens 604-611 areshown. Thus, in the conventional lead 402 shown in FIG. 4, eightconnector wires can be disposed in the outer lumens 604-611 andelectrically coupled to eight electrodes.

FIGS. 7A-7D show four different embodiments of transversecross-sectional views of the lead 502 that are each configured andarranged to receive up to twice as many conductive wires as theconventional lead 402 shown in FIGS. 4 and 6 without a correspondingincrease in the lateral circumference of the lead 502. Accordingly, inat least some embodiments, up to twice the number of conductive wiresmay be disposed in the lead 502 from the exemplary conventional lead 402and electrically couple with up to twice the number of electrodesdisposed on the distal end of the lead 502 from the exemplaryconventional lead 502.

In some embodiments, a single conductive wire extends through each outerlumen. FIG. 7A is a schematic transverse cross-sectional view of oneembodiment of the distal end of the lead 502. In FIG. 7A, the lead 502includes a center lumen 702 and a plurality of outer lumens 704-719.Each outer lumen 704-719 is configured and arranged for an individualconductive wire to extend along the length of each individual outerlumen 704-719. In FIG. 7A, sixteen circular-shaped outer lumens 704-719are shown. Thus, in some embodiments, sixteen connector wires can bedisposed in the outer lumens 704-719 and electrically coupled to sixteenelectrodes.

In other embodiments, two or more conductive wires may extend througheach outer lumen. FIG. 7B is a schematic transverse cross-sectional viewof a second embodiment of the distal end of the lead 502. In FIG. 7B,the lead 502 includes a center lumen 720 and a plurality of outer lumens722-729. Each outer lumen 722-729 is configured and arranged formultiple conductive wires to extend along the length of each individualouter lumen 722-729. In FIG. 7B, eight circular-shaped outer lumens722-729 are shown, with each outer lumen 722-729 configured and arrangedfor two conductive wires to extend within each outer lumen 722-729.Thus, in some embodiments, sixteen connector wires can be disposed inthe outer lumens 722-729 and electrically coupled to sixteen electrodes.

FIG. 7C is a schematic transverse cross-sectional view of a thirdembodiment of the distal end of the lead 502. In FIG. 7C, the lead 502includes a center lumen 730 and a plurality of outer lumens 732-739.Each outer lumen 732-739 is configured and arranged for multipleconductive wires to extend along the length of each individual outerlumen 732-739. In FIG. 7C, eight oval-shaped outer lumens 732-739 areshown, with each outer lumen 732-739 configured and arranged for twoconductive wires to extend within each outer lumen 732-739. Thus, insome embodiments, sixteen connector wires can be disposed in the outerlumens 732-739 and electrically coupled to sixteen electrodes. In FIG.7C, the outer lumens 732-739 each include a major axis, such as themajor axis 740, of the outer lumen 734. In FIG. 7C, the outer lumens732-739 are oriented such that the major axis of each of the outerlumens 732-739 is approximately perpendicular to a diameter of the lead502 which passed through a center of each of the outer lumens 732-739.For example, in FIG. 7C, the major axis 740 of the outer lumen 734 isapproximately perpendicular to the diameter 742 extending through thecenter of the outer lumen 734.

FIG. 7D is a schematic transverse cross-sectional view of a fourthembodiment of the distal end of the lead 502. In FIG. 7D, the lead 502includes a center lumen 744 and a plurality of outer lumens 746-753.Each outer lumen 746-753 is configured and arranged for multipleconductive wires to extend along the length of each individual outerlumen 746-753. In FIG. 7D, eight oval-shaped outer lumens 746-753 areshown, with each outer lumen 746-753 configured and arranged for twoconductive wires to extend within each outer lumen 746-753. Thus, insome embodiments, sixteen connector wires can be disposed in the outerlumens 746-753 and electrically coupled to sixteen electrodes. In FIG.7D the outer lumens 746-753 each include a major axis, such as the majoraxis 754 of the outer lumen 750.

In FIG. 7D, the outer lumens 746-753 are oriented such that the majoraxis of each of the outer lumens 746-753 is disposed at anon-perpendicular angle with respect to a diameter of the lead 502 whichpassed through a center of each of the outer lumens 746-753. Forexample, in FIG. 7D, the major axis 754 of the outer lumen 750 isdisposed at a non-perpendicular angle with respect to the diameter 756extending through the center of the outer lumen 750. In at least someembodiments, each of the outer lumens 746-753 are disposed at an anglein the range of 15 to 75 degrees or 30 to 60 degrees, for example, atapproximately a 45° angle, with respect to a diameter passing through acenter of each of the outer lumens 746-753.

In alternate embodiments, outer lumens can be configured and arranged toaccommodate additional conductive wires. Accordingly, the number ofmultiple conductive wires that can be disposed in an outer lumen mayvary. For example, there can be one, two, three, four, five, six, seven,eight, nine, ten, twelve, fourteen, sixteen, or more conductive wiresdisposed in an outer lumen. As will be recognized, other numbers ofconductive wires may also be disposed in an outer lumen.

FIG. 8 is a schematic transverse cross-sectional view of one embodimentof a conductive wire disposed in each outer lumen of the exemplaryconventional lead 402. In FIG. 8, an individual conductive wire, suchconductive wire 802, is disposed in each of the outer lumens (604-611 inFIG. 6). FIG. 9A is a schematic transverse cross-sectional view of oneembodiment of a conductive wire disposed in each outer lumen of the lead502. In FIG. 9A, an individual conductive wire, such as the conductivewire 902, is disposed in each of the outer lumens (704-719 in FIG. 7A).

FIG. 9B is a schematic transverse cross-sectional view of one embodimentof multiple conductive wires disposed in each outer lumen of the lead502. In FIG. 9B, two conductive wires, such as conductive wires 904 and906, are shown disposed in each of the outer lumens (722-729 in FIG.7B). In at least some embodiments, when multiple conductive wires aredisposed in an individual outer lumen of a lead, an insulated coatingdisposed over each of the conductive wires is visually distinct from theinsulated coating disposed over other conductive wires disposed in thesame outer lumen to facilitate assembly or repair of a lead. Forexample, multiple conductive wires disposed in an individual outer lumenmay include insulated coatings of different colors. In FIG. 9B and insubsequent figures, different cross-hatching is used for each conductivewire disposed in an outer lumen to signify that each conductive wireincludes an insulated coating that is visually distinct from otherconductive wires.

FIG. 9C is a schematic transverse cross-sectional view of one embodimentof multiple conductive wires disposed in each outer lumen of the lead502. In FIG. 9C, two conductive wires, such as conductive wires 908 and910, are shown disposed in each of the outer lumens (732-739 in FIG.7C). FIG. 9D is a schematic transverse cross-sectional view of oneembodiment of multiple conductive wires disposed in each outer lumen ofthe lead 502. In FIG. 9D, two conductive wires, such as conductive wires912 and 914, are shown disposed in each of the outer lumens (746-753 inFIG. 7D).

In some embodiments, an end plug can be disposed in a central lumen tostiffen a proximal end of a lead to facilitate insertion of the proximalend of the lead into a connector. FIG. 10A is a schematic side view ofone embodiment of a portion of a proximal end of the lead 502. Theproximal end 1004 of the lead 502 includes a plurality of terminals1006, such as the terminal 1008, and a central lumen 1010. Note that, inFIG. 1 OA and in subsequent figures, only a subset of the terminals 1006are shown for clarity of illustration. FIG. 10B is a schematic side viewof one embodiment of a portion of an end plug 1012. The end plug 1012includes an end cap 1014 and a rod 1016 mounted to the end cap 1014. Inone embodiment, the rod 1016 is welded to the end cap 1014. The end cap1014 and the rod 1016 can be made from any number of materials that arestiffer than a proximal end of a lead and are biocompatible. Suitablematerials include metals, ceramics, plastics, and the like orcombinations thereof. The end cap 1014 and the rod 1016 can be made fromthe same material or can be made from different materials.

In at least some embodiments, the end plug 1012 is configured andarranged for disposal in the central lumen (1010 in FIG. 10A) of theproximal end (1004 in FIG. 10A) of the lead (502 in FIG. 10A). FIG. 10Cis a schematic side view of one embodiment of the end cap 1014 and therod 1016 disposed in the central lumen 1010 of the proximal end 1004 ofthe lead 502. FIG. 10D is a schematic transverse cross-sectional view ofone embodiment of the rod 1016 disposed in the central lumen 1010 of theproximal end 1004 of the lead 502.

In at least some embodiments, when multiple conductive wires aredisposed in an individual outer lumen of a lead, the multiple conductivewires can be electrically coupled to adjacent terminals disposed on aproximal end of the lead to facilitate assembly or repair of the lead.In at least some embodiments, when multiple conductive wires aredisposed in an individual outer lumen of a lead, the multiple conductivewires can be electrically coupled to adjacent electrodes disposed on adistal end of the lead to facilitate assembly or repair of the lead. Inat least some embodiments, when multiple conductive wires are disposedin an individual outer lumen of a lead, the multiple conductive wirescan be electrically coupled to adjacent terminals disposed on a proximalend and adjacent electrodes disposed on the distal end of the lead tofurther facilitate assembly or repair of the lead.

Sometimes spacers, such as polyurethane spacers, are formed andpositioned between adjacent terminals on a proximal end of a lead. In atleast some embodiments, in lieu of spacers, a resin can be injectedbetween adjacent terminals and between the most proximal terminal and anend cap disposed on the proximal end of a lead. FIGS. 11A-11C show oneembodiment of several possible steps performed during the fabrication ofa proximal end of a lead. FIG. 11A is a schematic side view of oneembodiment of a portion of a proximal end of a lead 1102 with terminals1104 and an end cap 1106 disposed in a central lumen (744 in FIG. 7D).Conductive wires, such as conductive wires (912 and 914 in FIG. 9D),disposed in outer lumens, such as outer lumen 751, are electricallycoupled to the terminals 1104.

FIG. 11B is a schematic side view of one embodiment of the portion ofthe proximal end of the lead 1102 with resin 1108 injected betweenadjacent terminals 1104 and between the most proximal terminal 1110 andthe end cap 1106. Many different resins may be used. For example, theresin can be silicone, polyurethane, PEEK, epoxy, and the like orcombinations thereof. For example, the resin can be liquid injected intoa mold that contains the terminals and the end cap. In at least someembodiments, the resin can be injected by placing the proximal end ofthe lead 1102 into a mold cavity with cylindrical pockets sized toreceive the terminals 1104 and the end cap 1106. The mold may be closedand the resin 1108 may be injected into the mold cavity to fill thespaces between the terminals 1304 and between the most proximal terminal1110 and the end cap 1106. Additionally, in some embodiments, the resin1108 may also fill any voids between the central lumen (744 in FIG. 7D)and the outer lumens (746-753 in FIG. 7D). In some embodiments, theresin 1108 may also fill any voids between an interior surface eachouter lumen and an exterior surface of one or more connector wiresdisposed in each of the outer lumens.

Once the resin 1108 has been injected and set, the terminals 1104 maystill have diameters that are greater than the diameters of theresin-filled spaces between adjacent terminals and between the mostproximal terminal 1110 and the end cap 1106. In at least someembodiments, when the terminals 1104 and the end cap 1106 have a largerdiameter than the resin-filled spaces, the terminals 1104 and the endcap 1106 can be ground down to a size and shape that is similar to thesize and shape of the resin-filled spaces. FIG. 11C is a schematic sideview of one embodiment of the portion of the proximal end of the lead1102 after the terminals 1104 and the end cap 1106 have been ground. Itwill be understood that in some embodiments of the manufacturing processshown in FIGS. 11A-11C, the manufacturing process is performed withoutan end cap being disposed in the proximal end of the lead.

One advantage of using an injected resin to fill in spaces betweenadjacent terminals instead of using spacers is that a mold can be usedto provide consistent spacing between adjacent terminals. Anotheradvantage is that voids around conductive wires and lumens can be filledin to reduce relative movement between conductive wires and lumens. Yetanother advantage is that resin can be used to facilitate attachment ofthe end cap to the proximal end of the lead. Another advantage is thatusing an injected resin may reduce assembly time during leadmanufacture.

FIG. 12 is a schematic overview of one embodiment of components of anelectrical stimulation system 1200 including an electronic subassembly1210 disposed within a control module. It will be understood that theelectrical stimulation system can include more, fewer, or differentcomponents and can have a variety of different configurations includingthose configurations disclosed in the stimulator references citedherein.

Some of the components (for example, power source 1212, antenna 1218,receiver 1202, and processor 1204) of the electrical stimulation systemcan be positioned on one or more circuit boards or similar carrierswithin a sealed housing of an implantable pulse generator, if desired.Any power source 1212 can be used including, for example, a battery suchas a primary battery or a rechargeable battery. Examples of other powersources include super capacitors, nuclear or atomic batteries,mechanical resonators, infrared collectors, thermally-powered energysources, flexural powered energy sources, bioenergy power sources, fuelcells, bioelectric cells, osmotic pressure pumps, and the like includingthe power sources described in U.S. Patent Application Publication No.2004/0059392, incorporated herein by reference.

As another alternative, power can be supplied by an external powersource through inductive coupling via the optional antenna 1218 or asecondary antenna. The external power source can be in a device that ismounted on the skin of the user or in a unit that is provided near theuser on a permanent or periodic basis.

If the power source 1212 is a rechargeable battery, the battery may berecharged using the optional antenna 1218, if desired. Power can beprovided to the battery for recharging by inductively coupling thebattery through the antenna to a recharging unit 1216 external to theuser. Examples of such arrangements can be found in the referencesidentified above.

In one embodiment, electrical current is emitted by the electrodes 134on the paddle or lead body to stimulate nerve fibers, muscle fibers, orother body tissues near the electrical stimulation system. A processor1204 is generally included to control the timing and electricalcharacteristics of the electrical stimulation system. For example, theprocessor 1204 can, if desired, control one or more of the timing,frequency, strength, duration, and waveform of the pulses. In addition,the processor 1204 can select which electrodes can be used to providestimulation, if desired. In some embodiments, the processor 1204 mayselect which electrode(s) are cathodes and which electrode(s) areanodes. In some embodiments, the processor 1204 may be used to identifywhich electrodes provide the most useful stimulation of the desiredtissue.

Any processor can be used and can be as simple as an electronic devicethat, for example, produces pulses at a regular interval or theprocessor can be capable of receiving and interpreting instructions froman external programming unit 1208 that, for example, allows modificationof pulse characteristics. In the illustrated embodiment, the processor1204 is coupled to a receiver 1202 which, in turn, is coupled to theoptional antenna 1218. This allows the processor 1204 to receiveinstructions from an external source to, for example, direct the pulsecharacteristics and the selection of electrodes, if desired.

In one embodiment, the antenna 1218 is capable of receiving signals(e.g., RF signals) from an external telemetry unit 1206 which isprogrammed by a programming unit 1208. The programming unit 1208 can beexternal to, or part of, the telemetry unit 1206. The telemetry unit1206 can be a device that is worn on the skin of the user or can becarried by the user and can have a form similar to a pager, cellularphone, or remote control, if desired. As another alternative, thetelemetry unit 1206 may not be worn or carried by the user but may onlybe available at a home station or at a clinician's office. Theprogramming unit 1208 can be any unit that can provide information tothe telemetry unit 1206 for transmission to the electrical stimulationsystem 1200. The programming unit 1208 can be part of the telemetry unit1206 or can provide signals or information to the telemetry unit 1206via a wireless or wired connection. One example of a suitableprogramming unit is a computer operated by the user or clinician to sendsignals to the telemetry unit 1206.

The signals sent to the processor 1204 via the antenna 1218 and receiver1202 can be used to modify or otherwise direct the operation of theelectrical stimulation system. For example, the signals may be used tomodify the pulses of the electrical stimulation system such as modifyingone or more of pulse duration, pulse frequency, pulse waveform, andpulse strength. The signals may also direct the electrical stimulationsystem 1200 to cease operation, to start operation, to start chargingthe battery, or to stop charging the battery. In other embodiments, thestimulation system does not include an antenna 1218 or receiver 1202 andthe processor 1204 operates as programmed.

Optionally, the electrical stimulation system 1200 may include atransmitter (not shown) coupled to the processor 1204 and the antenna1218 for transmitting signals back to the telemetry unit 1206 or anotherunit capable of receiving the signals. For example, the electricalstimulation system 1200 may transmit signals indicating whether theelectrical stimulation system 1200 is operating properly or not orindicating when the battery needs to be charged or the level of chargeremaining in the battery. The processor 1204 may also be capable oftransmitting information about the pulse characteristics so that a useror clinician can determine or verify the characteristics.

The above specification, examples and data provide a description of themanufacture and use of the composition of the invention. Since manyembodiments of the invention can be made without departing from thespirit and scope of the invention, the invention also resides in theclaims hereinafter appended.

What is claimed and desired to be protected by Letters Patent of theUnited States is:
 1. A lead assembly comprising: a lead with a distalend, a proximal end, and a longitudinal length, the lead comprising aplurality of electrodes disposed along the distal end, a plurality ofterminals disposed along the proximal end, a central lumen defined bythe lead and extending along the longitudinal length of the lead fromthe proximal end to the plurality of electrodes, a plurality of outerlumens defined by the lead and extending along the longitudinal lengthof the lead from the plurality of terminals to the plurality ofelectrodes, and a plurality of conductive wires extending along thelongitudinal length of the lead and electrically coupling the pluralityof electrodes to the plurality of terminals; and an end plug configuredand arranged for insertion into the central lumen at the proximal end ofthe lead, the end plug configured and arranged to stiffen the proximalend of the lead to facilitate insertion of the proximal end of the leadinto a connector.
 2. The lead assembly of claim 1, wherein each of theplurality of outer lumens is oval-shaped with a major axis and atransverse axis perpendicular to the major axis.
 3. The lead assembly ofclaim 2, wherein for each of the plurality of outer lumens the majoraxis is disposed perpendicular to a diameter of the lead which passesthrough a center of that outer lumen.
 4. The lead assembly of claim 2,wherein for each of the plurality of outer lumens the major axis isdisposed at an angle in the range of 15 to 60 degrees relative to adiameter of the lead which passes through a center of that outer lumen.5. The lead assembly of claim 2, wherein for each of the plurality ofouter lumens the outer lumen is symmetrical about the major axis.
 6. Thelead assembly of claim 2, wherein for each of the plurality of outerlumens the outer lumen is symmetrical about the transverse axis.
 7. Thelead assembly of claim 2, wherein for each of the plurality of outerlumens the outer lumen is symmetrical about both the major axis and thetransverse axis.
 8. The lead assembly of claim 1, wherein the entirelongitudinal length of the lead is isodiametric.
 9. The lead assembly ofclaim 1, wherein the end plug comprises an end cap and a rod coupled tothe end cap, wherein the rod is configured and arranged for insertioninto the central lumen at the proximal end of the lead.
 10. The leadassembly of claim 9, wherein the rod is hollow.
 11. The lead assembly ofclaim 1, wherein a portion of the end plug is disposed in the centrallumen.
 12. The lead assembly of claim 1, further comprising a leadsplitter configured and arranged to electrically couple with the lead,the lead splitter having a distal end and a plurality of proximal tails,the lead splitter comprising a connector disposed at the distal end forreceiving the proximal end of the lead, the connector comprising aconnector housing defining at least one port for receiving the proximalend of the lead, and a plurality of connector contacts disposed in theconnector housing, the connector contacts configured and arranged tocouple electrically to at least one terminal on the proximal end of thelead, and each of the plurality of proximal tails having a distal endand comprising at least one lead-splitter terminal and at least onelead-splitter conductive wire, the lead-splitter terminal disposed atthe distal end and the at least one lead-splitter conductive wireelectrically coupling at least one of the plurality of connectorcontacts of the connector to the at least one lead-splitter terminal.13. An electrical stimulating system comprising: the lead assembly ofclaim 1; a control module configured and arranged to electrically coupleto the lead of the lead assembly, the control module comprising ahousing, and an electronic subassembly disposed in the housing; and aconnector configured and arranged for receiving the lead of the leadassembly, the connector comprising a connector housing defining at leastone port for receiving the proximal end of the lead of the leadassembly, and a plurality of connector contacts disposed in theconnector housing, the connector contacts configured and arranged tocouple to at least one terminal of the plurality of terminals disposedat the proximal end of the lead of the lead assembly.
 14. A leadassembly comprising: a lead with a distal end, a proximal end, and alongitudinal length, the lead comprising a plurality of electrodesdisposed along the distal end, a plurality of terminals disposed alongthe proximal end, a central lumen defined by the lead and extendingalong the longitudinal length of the lead from the proximal end to theplurality of electrodes, and a plurality of conductive wires extendingalong the longitudinal length of the lead and electrically coupling theplurality of electrodes to the plurality of terminals; and an end plugconfigured and arranged for insertion into the central lumen at theproximal end of the lead, the end plug configured and arranged tostiffen the proximal end of the lead to facilitate insertion of theproximal end of the lead into a connector.
 15. The lead assembly ofclaim 14, wherein the end plug comprises an end cap and a rod coupled tothe end cap, wherein the rod is configured and arranged for insertioninto the central lumen at the proximal end of the lead.
 16. The leadassembly of claim 15, wherein the rod is hollow.
 17. The lead assemblyof claim 15, wherein the rod is disposed in the central lumen.
 18. Thelead assembly of claim 14, wherein a portion of the end plug is disposedin the central lumen.
 19. The lead assembly of claim 14, furthercomprising a lead splitter configured and arranged to electricallycouple with the lead, the lead splitter having a distal end and aplurality of proximal tails, the lead splitter comprising a connectordisposed at the distal end for receiving the proximal end of the lead,the connector comprising a connector housing defining at least one portfor receiving the proximal end of the lead, and a plurality of connectorcontacts disposed in the connector housing, the connector contactsconfigured and arranged to couple electrically to at least one terminalon the proximal end of the lead, and each of the plurality of proximaltails having a distal end and comprising at least one lead-splitterterminal and at least one lead-splitter conductive wire, thelead-splitter terminal disposed at the distal end and the at least onelead-splitter conductive wire electrically coupling at least one of theplurality of connector contacts of the connector to the at least onelead-splitter terminal.
 20. An electrical stimulating system comprising:the lead assembly of claim 14; a control module configured and arrangedto electrically couple to the lead of the lead assembly, the controlmodule comprising a housing, and an electronic subassembly disposed inthe housing; and a connector configured and arranged for receiving thelead of the lead assembly, the connector comprising a connector housingdefining at least one port for receiving the proximal end of the lead ofthe lead assembly, and a plurality of connector contacts disposed in theconnector housing, the connector contacts configured and arranged tocouple to at least one terminal of the plurality of terminals disposedat the proximal end of the lead of the lead assembly.